A. Field of the Invention
The Invention is a post support for a fence or handrail post. The invention is also a retaining wall including the post support and is also a method of building a retaining wall using the post support.
B. Statement of the Related Art
As used in this document, a ‘retaining wall’ is a barrier used to achieve an abrupt change of grade of land between a higher elevation and a lower elevation. The retaining wall supports earth at a higher elevation on one side of the retaining wall and prevents the movement of the earth to the side having a lower elevation. As used in this document, the term ‘earth’ means soil of any type, including loam, sand, clay and fill material. The term ‘fill material’ includes crushed stone of any size, gravel, quarry dust, sand, rock, or masonry and includes any material imported to a location that changes the grade of the location. A properly designed and constructed retaining wall is an engineered structure that will resist the pressure of earth and fill on the higher elevation side of the retaining wall, even when the earth and fill is saturated with water.
The strength of a retaining wall may be selected for a particular application; for example, the retaining wall may be a very strong poured concrete wall used as a basement wall. Conversely, the retaining wall may be laterally weak, as in a stack wall using in landscaping. ‘Stack wall’ means a type of retaining wall composed of stones or concrete blocks that are stacked one on top of another and that are held in place by the force of gravity and without mortar. Only the weight of the stones or blocks and the mechanical interference between adjacent stones or blocks keep the stack wall in place and holds back the earth and fill material.
The abrupt elevation change across the retaining wall may present a hazard to persons, pets or other animals; namely, a person, pet or other animal may fall from the higher elevation side of the retaining wall. To avoid the potential hazard, a fence or handrail supported by posts may be installed on the higher elevation side of the retaining wall.
Where the lateral strength of the retaining wall is adequate, the posts supporting the fence or handrail may be attached directly to the retaining wall and any lateral load applied to the fence or handrail is supported by the strong retaining wall. A ‘lateral load’ is a force, for example a force applied by a person or animal, against the fence or handrail and from the direction of the higher elevation side of the retaining wall toward the lower elevation side of the retaining wall and generally normal to a plane defined by the surface of the retaining wall. Attaching the posts to the retaining wall has the advantage of providing the maximum usable ground area above the retaining wall. Where the retaining wall is not laterally strong, such as a stack wall, attaching the posts directly to the top of the retaining wall may cause the retaining wall to collapse when a lateral load is applied to the fence or handrail.
As an alternative to attaching the fence or handrail posts to the retaining wall, the bottom end of the posts may be buried in the earth or fill on the higher elevation side of the retaining wall. Where the retaining wall is laterally strong, the posts may be buried near the retaining wall, preserving the use of the ground on the higher-elevation side of the retaining wall.
Where the retaining wall is a stack wall or is otherwise not laterally strong, burying the posts close to the retaining wall may allow a lateral load applied to the fence or handrail to be transferred to the retaining wall, which may cause the retaining wall to collapse. To avoid collapse of the laterally weak retaining wall, the posts must be buried well back from the retaining wall so that a lateral load applied to the fence or handrail is supported by the surrounding earth or fill and is not transferred to the retaining wall. Setting the posts back from the retaining wall results in loss of use of ground on the higher elevation side of the retaining wall, which is not desirable.
The prior art does not teach a post support that allows the fence or handrail to be constructed immediately adjacent to a laterally weak retaining wall, such as a stack wall, and thus preserving the use of the ground above the laterally weak retaining wall.